Annealing laser-melted ductile iron by pulsed Nd:YAG laser radiation

Laser-melted ductile iron was rapidly annealed by pulsed Nd:YAG laser beam irradiation. The cementite-graphite phase transformation occurred rapidly during the short duration pulsed laser beam scanning. As a result, novel iron-base alloys containing either ultra-fine nodular graphite particles or both rapidly solidified cementile and ultra-fine graphite particles have been fabricated. The unusually accelerated cementite-graphite phase transformation and the production of the ultra-fine novel microstructure were predominantly due to the micro-annealing effect of the cyclic temperature fluctuations induced by the pulsed laser beam radiation.